Method of improving adhesion

Abstract

A method is for improving adhesion between a semiconductor substrate and a dielectric layer. The method includes depositing a silicon dioxide adhesion layer onto the semiconductor substrate by a first plasma enhanced chemical vapor deposition (PECVD) process, and depositing the dielectric layer onto the adhesion layer by a second PECVD process. The first PECVD process is performed in a gaseous atmosphere comprising tetraethyl orthosilicate (TEOS) either in the absence of O 2 or with O 2 introduced into the process at a flow rate of 250 sccm or less.

What is claimed is: 
     
       1. A method of improving adhesion between a semiconductor substrate and a dielectric layer comprising the steps of:
 depositing a silicon dioxide adhesion layer onto the semiconductor substrate by a first plasma enhanced chemical vapor deposition (PECVD) process; and 
 depositing the dielectric layer onto the adhesion layer by a second PECVD process; 
 in which the first PECVD process is performed in a gaseous atmosphere comprising tetraethyl orthosilicate (TEOS) either in the absence of O 2  or with O 2  introduced into the process at a flow rate of 250 sccm or less. 
 
     
     
       2. A method according to  claim 1  in which O 2  is introduced into the process at a flow rate of 100 sccm or less. 
     
     
       3. A method according to  claim 2  in which O 2  is introduced into the process at a flow rate of 10 sccm or less. 
     
     
       4. A method according to  claim 1  in which the semiconductor substrate is silicon. 
     
     
       5. A method according to  claim 1  in which the dielectric layer is a silicon-containing material. 
     
     
       6. A method according to  claim 5  in which the dielectric layer is silicon nitride, silicon oxide or silicon carbide. 
     
     
       7. A method according to  claim 1  in which the first PECVD process uses a first RF signal to produce a plasma, wherein the first RF signal is of a frequency of less than 400 kHz. 
     
     
       8. A method according to  claim 1  in which the first PECVD process is performed in a gaseous atmosphere which comprises H 2 . 
     
     
       9. A method according to  claim 8  in which H 2  is introduced into the first PECVD process at a flow rate in the range 500 to 1200 sccm. 
     
     
       10. A method according to  claim 1  in which the silicon dioxide adhesion layer has a thickness of 1000 nm or less. 
     
     
       11. A method according to  claim 10  in which the silicon dioxide adhesion layer has a thickness of 200 nm or less. 
     
     
       12. A method according to  claim 1  in which the adhesion layer has a CH x :SiO ratio of at least 0.3% as calculated by comparing peak areas obtained by FTIR which are associated with CH x  and SiO absorptions, wherein x is 1 to 3. 
     
     
       13. A method according to  claim 12  in which the CH x :SiO ratio is at least 3%. 
     
     
       14. A method according to  claim 1  in which the first PECVD process is performed at a pressure in the range 3.0 to 4.0 Torr. 
     
     
       15. A method according to  claim 14  in which the first PECVD process is performed at a pressure in the range 2.5 to 3.5 Torr. 
     
     
       16. A method according to  claim 1  in which the first PECVD process is performed at a temperature in the range 100 to 200° C. 
     
     
       17. A structure comprising a semiconductor substrate, a dielectric layer and a silicon dioxide adhesion layer formed between the semiconductor substrate and the dielectric layer, the structure being manufactured by a method according to  claim 1 .